The domestic legislation of almost every nation in the world now requires doors, especially those in such public buildings as railroad stations, department stores, auditoriums, etc., to be constructed so as to be manageable by people in wheelchairs, with baby carriages, or on crutches without assistance. The doors must also be capable of rapidly, reliably, and smoothly opening wide in an emergency to allow the people inside to escape.
The former requisite, ensuring access to handicapped people, can usually be satisfied only with automatic sliding doors. Existing sliding doors, however, are not appropriate for ensuring escape and rescue routes as well.
A two-panel automatic sliding door especially intended to provide escape and rescue routes is known from French A 1 374 224. Each panel has a swinging component articulated to a non-swinging component. The swinging component of the panel snaps into the non-swinging component such that, when the middle of the door is pressed from inside, the swinging component will also open out.
A similar sliding door, which divides more or less at the middle, is disclosed in Swiss A 508 122. Dividing a two-panel door at the middle is known from U.S. Pat. No. 3,811,489. Although this approach does unobstruct the escape route to a certain extent in an emergency, it is an unsatisfactory solution.
A mechanism for closing a sliding gate can be derived from German Patent 2 853 772. The gate's drive mechanism is coupled in through a variable electromagnetic clutch and a downstream friction clutch. Once the gate's panel has been swung out and the rotary clutch is disconnected from the friction clutch, the resultant torque stored in an operations reservoir will be powerful enough to restore the panel. Closing mechanisms of this type are employed in particular in fire doors.
A two-panel automatic sliding door is known from European Patent A 163 942. Each panel has a swinging component articulated to a sliding but non-swinging component and resiliently secured such that, when the middle of the door is pressed from inside, the swinging components will swing out and simultaneously force the non-swinging components back.
In this embodiment as well, pressure must be applied from inside against the swinging components before they will swing out. In the event of a power failure, the two other components will not travel back, and the free access is sometimes so small that people hurling themselves against it in a panic will be injured or even killed.